Heat-developable photographic materials often contain a base or a base precursor, for the purpose of acceleration of development under heat. For this, a base precursor substance which releases a basic substance by the action of heat is preferably used, in view of the preservation stability of the photographic material.
However, many base precursors are often accompanied by serious fog during development. In addition, some of them tend to partially decompose during preservation, resulting in deterioration of photographic characteristics of the photographic material. Under these circumstances, further improvement is required with respect to base precursors used in photographic materials.